1. Field of the Invention
Embodiments of the present invention relate to an image sensor and a method of manufacturing the same.
2. Description of Related Art
In general, an image sensor formed as a semiconductor device for converting an optical image into an electric signal may include a charge coupled device (CCD) or a complementary metal oxide silicon (CMOS) image sensor (CIS).
A CIS may include a pixel array, each unit pixel in the array including a photodiode and a MOS transistor formed therein. Electric signals of each unit pixel may sequentially be detected by a switching method to detect an image.
The conventional CIS device may include a pixel array including photodiodes and a peripheral region including a logic circuit.
In the image sensor, the pixel array, which is a light receiving region, should be electrically isolated from a peripheral region that processes only the electric signals.
In the conventional art, however, it is difficult to completely isolate an epitaxial layer in the pixel array from that in the peripheral region. That is, leakage current and noise affect the peripheral region through a sub-epitaxial layer, i.e., the lowermost layer, of the pixel array.